(a) Field of the Invention
The present invention concerns protective structures for shut-off valves of transportable toxic gas containers, of the type comprising a cylindrical metallic hood unlockably mounted on the container, around the shut-off valve.
(b) Description of Prior Art
For the transportation of containers, typically bottles, containing toxic gases, in particular arsine or phosphine, safety measures have led to provide, all around the valve for the distribution of the gas contained in the container, a hood, of generally cylindrical configuration, made by stamping a sheet iron and screwed on a sleeve which is unitary with the container at the level of the base of the valve. To complete this protection it has also been proposed to place the containers, during transportation, in reinforced baskets which may contain one or more containers and including a lockable door, according to a difficult arrangement, which is not easy to put into operation, and which considerably raises the costs of transportation of the gas.
The Applicant has realized, from an examination of the accident and incident reports resulting from the falls of containers, for example from the platform of a truck travelling at 80 Km/h, that the possibilities of leaks never took place by reason of a break down or crack in the container itself, but always because of damages caused at the level of the valve.